Qualitative And Quantitative Studies On Adsorbed Behavior Of Aromatic Compounds By Resins

In this article，NDA-150and XAD-4were chosen as adsorbents.Salicylic acid,phenol, aniline, benzoic acid,2-naphthol,1-naphthylamine and naphthalene werechosen as adsorbates. A quantitative research of the adsorption behavior was carriedout thourgh static adsorption thermodynamics and kinetics. A qualitative study of theadsorption behavior was carried out thourgh QSPR.We can get the followingconclusions:(1) Compared with resin XAD-4, the resin NDA-150has higher specific surfacearea, richer microporus structure and more functional groups which are easy to formhydrogen bond.The resin NDA-150has an apparently more obvious adsorption effecton aromatic compounds under the same experimental conditions because of thesefactors.(2) Within the experimental concentration and temperature limits, theadsorptions of salicylic acid, phenol, aniline, benzoic acid,2-naphthol and1-naphthylamine on NDA-150conform to Langmuir equation, naphthalene accordswith Freundlich equation.When refers to the resin XAD-4, the seven aromaticcompounds all conform to the Freundlich equation.(3) According to the static state adsorption thermodynamics research, theadsorption of aromatic compounds on the two resins is an automatic, exothermicprocess driven by enthalpy.(4) Under the same experimental conditions, adsorption capacity of aromaticcompounds on the two kinds of resins is salicylic acid <phenol <aniline <benzoicacid <2-naphthol <1-naphthylamine.(5) The QSPR model shows: the adsorption equilibrium constant KLof theLangmuir equation of aromatic compounds on the NDA-150is positively correlatedwith hydrophobic parameter logP, while it negatively related to the temperature T, thehydrogen bond acidity parameters A of solute molecular and the characteristics ofvolume V. The order of the relative influences of the four variables is hydrophobicparameter logP> hydrogen bond acidity A> solute molecular size V> temperature T.In addition, the relative influences of the four variables on the adsorption were50%,31%,10%and9%.(6) The QSPR model shows: the adsorption equilibrium constant KFof theFreundlich equation of aromatic compounds on the XAD-4is positively correlatedwith hydrophobic parameter logP, while it negatively related to the temperature T, the hydrogen bond acidity parameters A of solute molecular and polarity S of molecular.The order of the relative influences of the four variables is hydrophobic parameterlogP> hydrogen bond acidity A> polarity of molecular S> temperature T. In addition,the relative influences of the four variables on the adsorption were44%,38%,14%and5%.